ELS detector

jamilM

<p><span>I am using UPLC with ELS detector for analysing Sugars in Honey.I in the instrument method I put a programe to change tha gain during the run in the events , but it did not change. also is there a suitable column for analysing sugars with uplc since I am using an normal HPLC coulmn (amine column)</span></p>

dougm

Although I cannot answer your ELSD question, I can answer your question about a new UPLC column chemistry that we have developed for retaining and separating polar analytes such as saccharides/sugars/carbohydrates in HILIC mode. Next month at Pittcon in Chicago Waters will launch the ACQUITY UPLC BEH Amide column. This column retains polar analytes via hydrophilic interaction chromatography (HILIC) and does a very good job separating compounds such as sugars. Note that this is an amide chemistry not an amino chemistry.

If you would like to learn more about this new chemistry and what it can do please go here to view a poster presented last fall by Waters scientists at the AOAC Meeting.

If you have any additional questions, please let us know.

--Doug

ACQUITYEPM

Greetings jamilM,

I was very concerned by your comment indicating that you were unable to change the ELSD gain setting through a timed event. I work within the Waters Evaluation organization and was worried that we had, somehow, missed this functionality. Just through coincidence, I happen to be, currently, working with an ELSD. It was reasonably simple for me to insert a timed event in my instrument method and confirm the functionality of the gain timed event.

The attached file demonstrates a change of gain on the ELSD from 100 to 500 at 9.5 minutes into the run. The top chromatogram is an example of peanut oil separated by non-aqueous reverse phase. There are eight significant peaks. Actually, there are a few more due to some co-elution, but for the sake of this discussion, let's agree on eight. The first peak is quite small followed by three large components. These first four peaks are followed by four additional (again, really more like six), longer chain components at a much reduced response. The lower chromatogram was generated with an increase in ELSD gain from 100 to 500 at 9.5 minutes. Please notice the slight baseline offset at the time of the gain change and the peak response of the last four peaks is, roughly, five times greater.

I performed this chromatography on an ACQUITY UPLC system updated to version 1.40 drivers and the Control Data System (CDS) was Empower 2154 at the Feature Release 3 version level. I do not believe that the behavior would be any different if the CDS was MassLynx since the command and control of the system components is, primarily, dictated by the driver version and not the CDS. However, I did, initially, fool myself into believing that the gain timed event did not function for the ELSD. I did this by making a change to a base Instrument Method, renaming the Instrument Method, but then forgetting to include the Instrument Method into the Method Set I was using in Empower Run Samples. I knew that I had changed the conditions of the Instrument Method, but hadn't actually requested that this new Instrument Method be run. Once I realized my mistake, I was able to convince myself that the gain timed event does function properly for the ACQUITY ELSD.

Regards,

pcb

jamilM

to solve the problem of changing the ELS gain. the instrument method and the method set were deleted and new instrument method and method set were created.using the same parameters of the deleted one.Then the gain changed ,

JAMIL